[Effects of astragalus injection on extracellular signal-regulated kinase pathway in cultured normal cardiac myocytes].
OBJECTIVE
To investigate the dose-effect relationship and time-effect relationship of astragalus injection on the protein expression of nitric-oxide synthase (NOS) and extracellular signal-regulated kinase (ERK) in cultured cardiac myocytes.


METHODS
(1) Ventricular myocytes of Sprague-Dawley rats were isolated, cultured, and incubated with astragalus injection of the concentrations of 0, 20, 100, 200, or 400 ml/L for 8 days. Cell growth curve was drawn. Automatic biochemical analyzer was used to detect the level of creatine kinase (CK). (2) Western blotting was used 2 h after incubation to observe the protein expression of ERK and nitric oxide synthase (NOS). (3) Myocytes were incubated with astragalus injection (200 ml/L) or with astragalus and PD98059, an ERK inhibitor, for 5, 15, 30, 60, and 120 min respectively, and Western blotting was used to detect the protein expression of ERK and NOS.


RESULTS
Astragalus of different concentrations showed no effect on the cell proliferation. Only the CK level of the astragalus 200 ml/L group was significantly higher than that of the control group (P < 0.05). Astragalus showed no dose-dependent effect on the ERK expression, and dose-dependently reduced the NOS expression level. 15 min after the co-incubation with astragalus 200 ml/L the ERK level of the myocytes decreased transiently, and then began to increase gradually since 15 min after the co-incubation; the NOS level began to increase since 60 min after the co-incubation (P < 0.05). After the addition of PD98059 the ERK expression significantly decreased (P < 0.05).


CONCLUSIONS
Astragalus injection has modulation effect on ERK and NOS expression. This effect is enhanced time-dependently at appropriate Astragalus concentration, but attenuated by high dose Astragalus injection.
Duan
Wei-dong
WD
Department of Hepatobiliary Surgery, General Hospital of PLA, Beijing, China.
He
Lei
L
Wang
Jin
J
Kang
Hong-jun
HJ
Song
Qing
Q
Jiang
Chao-guang
CG
Pan
Liang
L
D000818:Animals; D027883:Astragalus Plant / Q000737:chemistry*; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D028321:Plant Preparations / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D005419:Flavonoids; D028321:Plant Preparations; D019001:Nitric Oxide Synthase; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one